Patch-Source: https://github.com/void-linux/void-packages/blob/74f16232621ca8dfb6d244beff1df35a6df1647f/srcpkgs/llvm12/patches/libcxx-musl.patch

--- a/libcxx/include/locale
+++ b/libcxx/include/locale
@@ -742,7 +742,11 @@ __num_get_signed_integral(const char* __a, const char* __a_end,
         typename remove_reference<decltype(errno)>::type __save_errno = errno;
         errno = 0;
         char *__p2;
+#if defined(__linux__) && !defined(__GLIBC__)
+        long long __ll = strtoll(__a, &__p2, __base);
+#else
         long long __ll = strtoll_l(__a, &__p2, __base, _LIBCPP_GET_C_LOCALE);
+#endif
         typename remove_reference<decltype(errno)>::type __current_errno = errno;
         if (__current_errno == 0)
             errno = __save_errno;
@@ -782,7 +786,11 @@ __num_get_unsigned_integral(const char* __a, const char* __a_end,
         typename remove_reference<decltype(errno)>::type __save_errno = errno;
         errno = 0;
         char *__p2;
+#if defined(__linux__) && !defined(__GLIBC__)
+        unsigned long long __ll = strtoull(__a, &__p2, __base);
+#else
         unsigned long long __ll = strtoull_l(__a, &__p2, __base, _LIBCPP_GET_C_LOCALE);
+#endif
         typename remove_reference<decltype(errno)>::type __current_errno = errno;
         if (__current_errno == 0)
             errno = __save_errno;